I get paid to brush my teeth.

You may know someone who does, too. Perhaps it's that colleague whose teeth suddenly look like she's drinking a pot of coffee a day.

Be kind to us. Your smile depends on us, for we are the shock troops in the never-ending struggle against plaque, cavaties, and many of the other problems that may befall your teeth.

We are also foot soldiers in a war for something even more precious: market share. What was once a relatively mundane item -- the toothbrush -- has become a multimillion-dollar business, with dozens of manufacturers vying to out-clean the competition with products that Reach a little deeper, Flex a little more, and give your teeth a Total cleaning. And that's only part of the oral-hygiene market. Toothpaste and mouthwash ads also constantly tout "new and improved" products that are "clinically proven" to remove more plaque or get your teeth their whitest. And then there is the ultimate prize: the American Dental Association's seal of acceptance.

In order to win that seal and make those claims, someone has to put all those products to the test. And that's where I and your co-worker with the brown teeth come in. We are two of about 200 Penn people who participate in clinical trials conducted by the team of Drs. Samuel Yankell and Robert Emling.

The sort of applied research that Yankell and Emling do is not what most dental researchers find appealing, but it is vital to the $3-billion-a-year oral-hygiene products industry. Dental professionals can recommend products bearing the ADA seal of approval -- "Your dentist or hygienist is the only health-care professional who can recommend products sold over the counter," Yankell notes -- but in order to carry the seal, a product needs to pass established benchmarks in trials conducted according to an ADA standard protocol.

It just so happens that Yankell and Emling wrote the basic characteristics of the ADA protocol. "We had developed what we thought was an adequate protocol for testing toothbrushes for ADA approval," Yankell explained, noting that no product his team has recommended for approval has ever been denied it. "About eight years ago, the ADA announced it was reviewing its entire approval process and asked for suggestions for a new standard test protocol. We submitted ours.

"In 1989, the ADA published its new standard protocol. When we received the letter describing it, we were surprised -- it was essentially our protocol, almost verbatim."

Yankell was not a dentist by training; his Ph.D. is in nutrition. But he spent 14 years in industry, where he learned clinical testing practices such as doing indices for gingivitis and plaque deposits. This sparked his interest in dental product research, and in 1974 he joined the School of Dental Medicine faculty. He has been conducting clinical research trials ever since. (Because Dental School faculty must have clinical degrees, Yankell enrolled in Penn's dental hygiene program and received his registered dental hygienist degree in 1981.)

Yankell and Emling are almost constantly engaged in trials, varying in size from 12 to 180 participants and in duration from one week to six months. The trials generally fall into one of four main categories:

* The basic toothbrush study for ADA approval.

* Studies to support marketing claims made by manufacturers, or for comparative purposes. These usually follow the ADA protocol, but the results become the property of the manufacturer.

* Experimental studies to determine the effect of a new ingredient or product design. Yankell and Emling limit their tests of new ingredients to those approved by the FDA for over-the-counter sale.

* Long-term studies to determine the effect of a product over time. These usually involve toothpastes and mouth rinses. One of the main purposes of such studies is to see if microorganisms change in response to regular use of a product.

The two researchers also conduct smaller, more specialized studies, such as "exaggerated use" studies designed to test the safety of a new dental product.

All this brushing and gargling has made Penn's dental school a leading site for commercial clinical research. Yankell stated that in terms of applied research, Penn rates among the top seven university dental schools in the country.

One of the main reasons for the large amount of applied research is the enormous growth and change in the toothbrush industry since Johnson and Johnson introduced its angled Reach toothbrush in the late 1970s. Since then, Yankell said, "toothbrush sales have exploded" as companies rolled out new brush designs all focused on a single goal: "trying to get the brush to work better in spite of the user."

As a hygienist, Yankell is thoroughly versed in the proper brushing technique: bristles at a 45-degree angle to the tooth, and short, orbital brush strokes. "I can talk to patients about brushing technique until I'm blue in the face," he said, "and they will follow it for about two days. Then they slip right back into their old habits."

Hence all the radical new brush designs with uneven bristles, diamond-shaped heads, bendable handles and (in one design) three small heads designed to surround the tooth. The companies that make these brushes want to make sure they work at least as well as, if not better than, anything else currently on the market, and Yankell is happy to put them through their paces.

Some companies come to Yankell's lab because of the institutional prestige: "They like to have the University of Pennsylvania name associated with their research," he said. But he also thinks that the institutional safeguards Penn builds into its research and the rigorous standards his research team follows also add value. For example, he notes, "In order to adhere to the guidelines of Penn's Human Review Committee" -- a University-wide panel, on which Yankell sits, that sets criteria for research involving human subjects -- "we must get a full medical history for all of our subjects, and they must sign a consent form that describes the experimental procedures in detail, along with the anticipated risks. The requirements are the same for a toothbrush study as for, for example, a complete knee replacement."

And what happens with the results of these studies? That depends on their purpose. Research done to back up comparative marketing claims is usually proprietary, so a company can choose to keep the results secret. But there is a benefit to publishing the results, Yankell said: "If the information is published or presented at a conference, dentists can see the source of the study. A company's ads can also refer to published research, and a good dental professional will go back to read it" -- and perhaps, based on what he or she reads, will recommend the product to his or her patients.

Return to Compass Features for September 10, 1996